toyota82

I already checked fuses and what not. I believe it is the dimmer switch. I just wanted to ask if there is anything else i could check for.

81 4X4

Relay. These trucks have two relays under the dash, up above the steering column. Check those. My dash lights and running lights didn't work, and I jumped over to the other relay for a temporary fix. I have two relays new in the box if you need to buy any.

AR_yotaing

I had a dimmer problem. You should be able to jump the wires and see if they light up

FloridaHiluxGuy

Same problem but popped my TAIL fuse. Driving down the road, lost dash and tail driving lights and seen the flash from the fuse popping. Still had break, blinker and head lights. Chasing it down so far and made it to the power exiting the column light switch. Jump a hot to the driving light wire and dash lights come on. Jump a hot to the parking light wire and spark, dead short. I realize then that the short is somewhere in line with the parking lights, and I will chase it down when I have more than 15 minutes . BUT, Here's the new for me part... truck was running while playing this lil game and when the hot was jumped to the parking light wire the truck idled way down as if it was about to stall?

huskytike

Pretty much exact same circumstances as described by Floridahiluxguy. 15A fuse blew immediately whenever I activated "tail lights" - Headlights, turn, brake and reverse all good. I just purchased the truck and PO had put a 30A fuse in the slot as a short-term (read: long enough to make the sale) "fix". Probably owed to the oversized fuse I found two wires leaving the relay (green w/orange spot & red w/ yellow stripe and blk spot) had gotten a bit melty with one another. Cut out the affected sections of these wires and spliced in fresh, tore out dash and unwrapped harness to see if there was any other damage (all good on visual), but I still could not find the source of the original short. I had searched every section of the circuit from the cab back. Then, while reading another post on a similar issue (don't remember which now) the writer referred to "marker lights" - I had not considered the front of the truck because my headlights/flashers were fine, but sure enough the plastic on the two small orange markers on the side of the fender had rotted and the exposed clips were just laying inside the fender well.

Very happy to have resolved this (the hard way, of course). I've seen a lot of references to upgraded headlight harnesses - is there anything similar for tail lights? Based on all I'm reading I don't have the strongest faith in the wiring overall. I would love to just upgrade the whole harness, but I don't think I'm quite up for it.

I am very grateful for this resource.

FloridaHiluxGuy

I have NO marker lights present on the truck. The harness is there but the lights were missing when I got the truck. I need to check that, wires, relays.... As of late it has been my "day time truck" (lazy I know). So if it's gonna get dark I drive my Chevy, middle of the day I use the Yota. lol

huskytike

Does the fuse pop immediately when you close the circuit? Have you isolated it to the cab (disconnected the block behind the passengers seat)? The idle down when you jump the circuit makes sense because your short is drawing a lot of current and the alternator is putting that load on the engine.

Good luck hunting it down. I'll be curious to hear where you trace it to. As I said, eventually I'd like to replace the whole harness, but I've got to square away a few other projects before I take this truck out of commission for that long.

zuggie

Same problem with running lights and dash lights blowing the 15a fuse.
'90 base 22r.
After much persistence and a continuity meter I found that the miniature wedge bulb 1.4w behind the heat a/c bezel had blown and was shorting the circuit.
I hope this helps. I wouldn't wish this problem on a Chevy owner. lol

FloridaHiluxGuy

Wow that's crazy! Who'd thunk it??? I still been day time driving mine while building it and my 85. Not so much lazy anymore as preoccupied with other stuff. Thanks Huskytike and Zuggie, your words of inspiration and encouragement have motivated me to put this next on the "to do list" and quit avoiding it.